The present invention relates to semiconductor devices, and more particularly to a method and system for determining the flow rate in order to form contacts in a semiconductor device.
In order to provide contacts in a conventional semiconductor device, a conventional mask is used. The conventional mask is used in conjunction with a light source to develop a pattern on a photoresist mask on a semiconductor device. Light is diffracted by the mask to expose portions of a layer of photoresist on the semiconductor device. The mask material typically includes a phase shift material and/or chromium which lie on a quartz substrate. The conventional mask has apertures in the regions in which the contacts are to be formed. Once the photoresist mask on the semiconductor device is patterned, exposed portions of the semiconductor device can be etched to form contact holes, then refilled with a conductive material to form contacts. The mask itself is formed by patterning a layer of resist on mask materials. To form the conventional mask, portions of the resist layer are removed. The underlying mask material(s) are etched, thereby forming apertures in the conventional mask.
Although the conventional method for forming contacts in a semiconductor device functions, one of ordinary skill in the art will readily recognize that the contacts formed may have a different size than desired. During fabrication of the conventional mask, the resist on the mask materials may shrink. The rate of the shrinkage of the resist is known as the flow rate. Because of the flow rate, the size of the apertures in the mask may be different than desired. The size of the contacts formed may, therefore, be different than desired. Because the contacts do not have the desired dimension, the performance of the semiconductor device may suffer.
Accordingly, what is needed is a system and method for providing a semiconductor device having contacts with the desired dimensions. The present invention addresses such a need.
The present invention provides a method and system for determining a mask for fabricating semiconductor device. The method and system comprise patterning a resist layer on at least one mask material to provide a patterned resist layer. The patterned resist layer has a plurality of apertures therein. The plurality of apertures is for the plurality of features. The plurality of apertures has a plurality of apertures sizes and a plurality of aperture pitches. The method and system also comprise providing a test mask for a plurality of features using the resist layer. The test mask has the plurality of apertures therein. The method and system also comprise determining a plurality of flow rates for the plurality of aperture pitches and the plurality of aperture sizes based upon the plurality of features.
According to the system and method disclosed herein, the present invention allows the flow rates for a mask to be determined for different sizes and pitches of features, allowing a user to correct for the flow rates when fabricating the mask.